The present invention is directed to heat exchangers for heating, ventilating and air conditioning (HVAC) and refrigeration applications. More specifically, the present invention proposes an arrangement for circuiting the passages of the heat exchanger to improve the heat exchanger""s performance. The improved arrangement, defined as step circuiting for purposes of this application, allows a heat exchanger to be designed with an increased number of circuits in the first pass and a reduced number of circuits in subsequent passes.
The increased number of circuits in the first pass reduces the pressure drop throughout the heat exchanger. This becomes important with lower density refrigerants such as R134a and also becomes important as the diameter of passages within the heat exchanger are reduced. Additionally, a reduced number of circuits in subsequent passes allows the heat transfer coefficient to increase due to the higher velocity of the refrigerant within the coils. The combination of lowering the entering pressure drop and increasing the overall heat transfer coefficient produces a more effective heat exchanger.
Additionally, most units require a middle header to collect the liquid leaving a condensing heat exchanger and directed to the inlet of a subcooler portion of that heat exchanger. The present invention also proposes to apply the step circuiting throughout a condensing heat exchanger and continue it through the subcooler to thereby eliminate the middle header.
The present invention is intended to address and solve the problems of the prior art.
The present invention is directed to a heat exchanger including a stepped coil. It is an object, advantage and feature of the present invention to apply the use of the step coil throughout a condensing heat exchanger including the subcooler.
It is an object, feature and advantage of the present invention to eliminate at least one of the headers of a heat exchanger and thereby provide easier and improved manufacturing.
It is an object, feature and advantage of the present invention to eliminate a header on a condensing heat exchanger to thereby reduce the total number of joints with a subsequent reduction in potential leak sites.
It is an object, feature and advantage of the present invention to provide a three fingered e-bend. It is a further object, feature and advantage of the present invention to replace a middle header with this e-bend and thereby lower the cost to manufacture a heat exchanger.
It is an object, feature and advantage of the present invention to lower the pressure drop in the critical first pass of a heat exchanger. It is a further advantage and improvement of the present invention to increase the velocity and therefore the heat transfer coefficient in each subsequent pass of the heat exchanger. It is a further feature and advantage of the present invention to move a subcooling portion to the front of the heat exchanger so that cooler, rather than warmer, air flows across it, and to thereby improve performance. It is a further object, feature and advantage of the present invention to move the outlet of a heat exchanger from a bottom portion of the heat exchanger to a mid-portion and thereby facilitate the manufacturing of the heat exchanger.
It is an object, feature and advantage of the present invention to provide a heat exchanger having tubes arranged in patterns where each pattern is repeated a predetermined number of times to form the heat exchanger.
It is an object, feature and advantage of the present invention to provide a connector between the passes of the a heat exchanger where the connector has multiple inlets and single outlet. It is a further object, feature and advantage of the present invention that this connector have the shape of a capital xe2x80x9cExe2x80x9d.
It is an object, feature and advantage of the present invention to provide a pattern of passes in a heat exchanger where each pattern includes at least three passes and where each pattern is replicated to form the heat exchanger.
It is an object, feature and advantage of the present invention to reduce the number of tubes in each pass as fluid travels from the inlet to the outlet of the heat exchanger.
The present invention provides a heat exchanger including a first fluid to be cooled, a second fluid cooling the first fluid, and a containment structure containing the first fluid and including heat transfer elements in heat exchange relation with the second fluid. The structure also includes an inlet, an outlet, a face, and a first pattern set where the first pattern set includes first and second respective passages extending across the face and linearly connected to each other, the inlet, and the outlet. The number of first passages is greater than the number of second passages. The heat exchanger also includes a connector interconnecting the first passages with the second passages wherein the connector includes multiple inlets and a single outlet. The connector preferably has the shape of a capital
The present invention also provides a method of manufacturing a heat exchanger. The method comprises the steps of: forming a pattern set to control movement of a first fluid through a heat exchanger; providing multiple passes in each pattern set, and assembling a heat exchanger using multiples of the pattern set. Each pass includes one or more tubes. The number of tubes in each pass is less than or equal to the number of tubes in the previous pass as the distance from the inlet of the heat exchanger increases. The number of tubes in an initial pass is greater than the number of tubes in a final pass.
The present invention additionally provides a heat exchanger arrangement including a pattern of passes in a heat exchanger. Each pattern includes at least three passes, and each pass includes one or more tubes extending across a face of the heat exchanger. The number of tubes in a given pass is less than or equal to the number of tubes in a previous pass and the heat exchanger includes at least two passes with differing numbers of tubes.
The present invention further provides a heat exchanger including a plurality of longitudinally extending tubes grouped into at least first, second and third passes. The tubes in the first pass are serially connected with tubes in the second pass. The tubes in the second pass are serially connected with tubes in the third pass. The number of tubes in the first pass is greater than the number of tubes in the third pass. The heat exchanger also preferably includes an E-shaped connector located between the tubes of two different passes.
The present invention yet further provides an air cooled heat exchanger including a frame and a longitudinally extending heat exchanger surface arranged in the frame and supported thereby. The heat exchanger has an inlet, an outlet, and a plurality of parallel tubes having an inlet and an outlet and arranged in a pattern set. The heat exchanger also includes a fan moving air through the heat exchanger surface, a manifold distributing fluid from the inlet to the first pass set, and a first pass of tubes in the pattern set an inlet and an outlet. The heat exchanger includes a second pass of tubes in the pattern set in, and a third pass of tubes in the pattern set. Connectors transfer fluid from the outlets of the first pass to the inlets of the second pass, and from the outlets of the second pass to the inlets of the third pass. The number of tubes in the first pass is greater than or equal to the number of the tubes in the second pass and the number of tubes in the second pass is greater than or equal to the number of tubes in the third pass. The number of tubes in the first pass is greater than the number of tubes in the third pass.
The present invention yet further provides a tubular connector. The connector comprises at least a pair of inlet arms each having an inlet aperture; an outlet arm having an outlet aperture; and a body operatively connecting the inlet arms and the outlet arms. Preferably, the inlet arms and the outlet arms lie in a common plane, and the inlet arms and the outlet arm are parallel such that the inlet arms, the outlet arm and the body are arranged in an E-shape.